Air handling unit



Sept. 2, 1969 H. E. GOLD ET AL 3,464,487

AIR HANDLING'UNIT Filed Nov. 2, 1967 2 Sheets-Sheet 1 INVENTORS HAROLDEGOLD BY PAUL E. HAMMANN ATTORNEY.

Sept. 2, 1969 H. E. GOLD ET AL 3,464,487

AIR HANDLING'UNIT Filed Nov. 2. 1967 2 Sheets-Sheet 2 i WWW? INVENTORSHAROLD E. GOLD BY PAUL E. HAMMANN ATTORNEY FIG 2 FIG?! 3,464,487 AIRHANDLING UNIT Harold E. Gold and Paul E. Hammann, Bettendorf, Iowa,assignors to American Air Filter Company, Inc., Louisville, Ky., acorporation of Delaware Filed Nov. 2, 1967, Ser. No. 680,146 Int. Cl.F25b 29/00; F24f 13/04, 13/08 U.S. 'Cl. 165-16 Claims ABSTRACT OF THEDISCLOSURE An air inlet assembly for an air-conditioning unit whichprovides a damper arrangement to control both the quantity of airreturned to the air conditioning unit from the space served by the unitand the quantity of fresh air supplied to the unit, and mix the twostreams of air upstream of air-conditioning elements which can also beprovided in the unit.

BACKGROUND OF THE INVENTION Previous air-conditioning apparatus to heatand/or cool air for a space to be served by the unit, for example,multizone air handling units which can include air heating and aircooling means to provide selectively conditioned air to differentlocations within a building, have generally provided means for mixingfresh air with a selected quantity of air returned from the space served'by the unit. Various air inlet arrangements have been provided in suchair conditioners to selectively regulate the quantity of air introducedto the air-conditioning apparatus, but such arrangements have generallynot pro vided means for efiicient mixing of the return air and fresh airbefore redistribution to the spaces served by the unit.

Furthermore, previous air inlet arrangements have required severalexpensive motor-operated dampers to regulate the flow of fresh andreturn air to the air-conditioning unit and exhaust a portion of thereturn air from the unit. The air inlet dampers in such apparatus havebeen disposed in side-by-side relationship to direct the return airstream and fresh air stream in parallel flow paths. In some suchapparatus additional mixing dampers or battles are provided downstreamof the inlet dampers to mix the air streams prior to delivery to the airconditioning elements and in those air conditioners where mixing dampersor bafiies are not provided the streams of air are not mixed so somezones served by the unit receive primarily return air while other zonesreceive primarily fresh air and very few zones receive the desiredcombination of both.

SUMMARY OF THE INVENTION The present invention recognizes that it isdesirable to provide an air inlet chamber to thoroughly mix controlledportions of air returned from the served space with controlled portionsof fresh air drawn into the unit before the air passes through theair-conditioning elements.

The present invention provides a straightforward air inlet arrangementfor an air-conditioning apparatus which can include only two motoroperated dampers and advantageously provides means for efiicient mixingof return air and fresh air streams prior to the introduction ofcombined streams to the air-conditioning elements of the unit.Therefore, each area served by the airconditioning apparatus is providedwith a more uniform mixture of fresh air and return air.

The present invention further recognizes that by advantageouslydisposing the dampers controlling the fresh air supply and return airsupply within the air inlet States Patent 0 m 3,464,487 Patented Sept.2, 1969 chamber in partially facing relation, the two air streams areefiiciently mixed and large dampers can be used to reduce the pressuredrop experienced by the air stream passing through the dampers so thecapacity of the air moving equipment associated with theair-conditioning unit is increased.

Various other features of the present invention will become obvious tothose skilled in the air upon reading the disclosure set fotrhhereinafter.

More particularly, the present invention provides an air inlet assemblyto supply a stream of air to an airconditioning apparatus comprising: ahousing having a return air inlet communicating with the space served bythe air-conditioning apparatus, a fresh air inlet communicating with asource of fresh air, and an exhaust air outlet communicating with thereturn air inlet; means to supply air from the space served by the unitto the return air inlet and to supply fresh air to the fresh air inlet;first wall means, including first adjustable air damper means, disposedwithin the housing to define a return air inlet chamber within thehousing communicating with the return air inlet and the exhaust airoutlet; second wall means, including second adjustable damper means,disposed within the housing to define a fresh air inlet chambercommunicating with the fresh air inlet wherein the second damper meansis in partially facing relation with the first damper means so airemitted from the second damper means is directed into the stream of airemitted from the first damper means; damper operator means toselectively modulate the fisrt and second adjustable damper means toregulate the quantity of return air and quantity of fresh air flowingthrough each of the dampers; exhaust fan means disposed to blow exhaustair through the exhaust air outlet; and, control means to operate theexhaust air fan in response to the position of the adjustable first andsecond damper means.

It is to be understood that the description of the example of thepresent invention given hereinafter is not by way of limitation and thatvarious changes can be made in the arrangement, form, and configurationof the apparatus disclosed Without departing from the scope or spirit ofthe present invention.

Referring now to the drawings:

FIGURE 1 is a perspective view, in section, of one example of anapparatus in accordance with the present invention;

FIGURE 2 is an elevational view, partly in section, of the apparatusshown in FIGURE 1; and,

FIGURE 3 is a view taken along a plane passing through line 3-3 ofFIGURE 2.

The example of one air-conditioning device in accordance with thepresent invention as shown in FIGURE 1 includes a housing 1 having anair inlet section comprising a fresh air inlet 3, return air inlet 5, anexhaust air outlet 2, and first air flow control damper 4, and secondair flow control damper 6 disposed within housing 1 as hereinafterdescribed. Downstream of the air inlet assembly air treating elementscan be provided in the housing and can include, for example, an airfilter 16, air blowers 21, an air heating element 32, and air coolingelement 33.

Housing 1 can include a framework 1b adapted to receive panels In andrest on base frame constructed of channel members 10 as shown. An accessdoor 1d can be provided to permit inspection and service of the unit andfacilitate changing the air filter media as hereinafter described. Theunit is, advantageously, mounted in contiguous relation with the spaceto be served, for example, on the roof of a building with the return airinlet 5 in communicative relation with a return air manifold (not shown)from the spaces served by the unit.

In accordance with one feature of the present invention, as shown in thefigures, first and second air control dampers 4 and 6 are disposedwithin the housing in partially facing relation so the stream of airemitted from return air damper 6 and fresh air damper 4 are mixed.Damper 6 is disposed between wall members 13 and 13a which are connectedto one end of the damper 6 and the wall of housing 1, respectively, todefine a return air inlet chamber communicating with return air inlet 5and exhaust air outlet 2 which is provided in housing 1. Return airinlet 5 communicate with a return air manifold to return air from thespace served by the unit. Damper 4 is disposed within the housing andwalls 12 and 12a, respectively, are provided to have one end to beconnected to each end of damper 4 and to the wall of housing 1, asshown, to define a fresh air inlet chamber communicating with the freshair inlet 3 A louver 3a, FIGURE 2, can be provided to cover fresh airinlet 3 to prevent admission of undesirable materials into housin 1.

Air flow through each damper assembly is controlled by the position ofthe individual damper blades 4a and 6a of the dampers. The constructionof both dampers 4 and 6 is similar in that blades 4a and 6a of bothdampers pivot about shafts 7 to crank arms 8. Each arm 8 is pivotablyconnected to an operator rod 9 so that the respective damper is openedand closed in response to movement of operator rod 9. A motor operator11 is provided to selectively adjust the air flow opening through eachof the dampers and a linking rod 9a (FIGURE 2) is provided to connectmotor operator 11 to each damper rod 9, as shown. The damper motoroperator is actuated in response to changes in temperature of the streamof mixed air admitted to downstream air conditioning elements 32, 33 tomaintain a uniform selected temperature in the air stream. The airtemperature can be sensed by a thermal bulb 28 within housing 1, forexample, downstream of filter 16 as shown, and the temperature istransmitted to the damper motor operator by means of a conduit 29 anddamper motor 11 operates accordingly.

A fan 15 is provided adjacent the exhaust air outlet to exhaust returnair from the air-conditioning unit and fan 15 can be adapted to bedriven by a motor 15a as shown. It will be noted that a drop damper isprovided to cover exhaust air outlet 2 and is opened in response to flowof air through the exhaust air outlet 2, for example when fan isoperating. Damper 10 is closed when there is no air flow through outlet2 and most of the re turn air received by the unit is recirculatedthrough the unit.

Downstream of the air inlet assembly, and before heating element 32 andcooling element 33, an air filter 16 is provided to remove particulatematter from the air stream passing through the unit. The filter, asshown, can be of the roll type and can include a filter media supplyroll 14 and a filter media take-up roll 17 to provide a continuous sheet16 of filter media, for example spun glass, transversely across the airflow path so that the entire air stream passes through the media.Support means including a frame 19 having intermediate supports 18 canbe provided to maintain the media in air filtering relation within theair-conditioning unit. Media supply roll 14 and media take-up roll 17can be journaled in bearing means 14a and 170, respectively, and mediacan be advanced from roll 14 to roll 17 by turning take-up roll 17, forexample by crank means (not shown), to draw new media from the supplyroll into the air filtering zone. Idle rollers 20 can be provided atopposite edges of frame 19 to lend further support media 16 in airfiltering relation. When roll 14 of fresh media is exhausted, take-uproll 17 can be removed through the opening provided by removable panel1d and new roll 14 of media can be inserted through the opening to bereceived by journals 14a. The media is then threaded from roll 14 toroll 17. If desired, indicator means (not shown) can be provided tosignal the condition of the filter media and to give notification whenthe media has become clogged so clean media can be advanced into the airflow stream.

As shown in FIGURE 1, air blowers 21 can be provided within the unit toprovide a stream of air through the air-conditioning unit. In theexample of the figures, blowers 21 and a drive motor 23 are carried by achassis 22 as a compact unit. Chassis 22 can be spring mounted to theair conditioner frame member for example by springs 26, to isolatehousing 1 from vibrations associated with operation of the blowerassembly. The arrangement, as shown, provides a single drive shaft 24 sothat only one motor is required to operate blowers 21. It will befurther noted that blowers 21 are located in housing 1 to provideinduced draft through the air inlet and the air filtering sections, andforced draft through the air heating and cooling elements downstream ofthe blowers. The outlets from blowers 21 communicate with an opening inwall 27 and are sealed (by seals 31) along the edges to wall member 27,which extends transversely across the housing so all the air emittedfrom the blower passes through the opening in wall 27 to the downstreamair heating and air cooling elements 32 and 33.

-Air heating element 32 and air cooling element 33 are disposed in overand under relationship within the housing as shown in the figures. Ahorizontal panel member 35 extends from the lower side of air heatingelements 32 to the upper side of air cooling element 33, as shown, todefine lower and upper air flow paths 34, 38, respectively. A horizontalpanel member 37 extends downstream from the cooling element 33 and isjoined to an outlet damper assembly in sealing relationship to preventair flow from the upper flow path to the lower flow path, and viceversa, downstream of cooling element 33. While a heating element 32 asshown in the figures is a direct fired heater, it will be recognizedthat other type heating elements, for example hot water heat exchangers,can be provided. The cooling element 33 shown in the example of thefigures represents a refrigerant evaporator having a condensedrefrigerant inlet 39 and an evaporated refrigerant outlet 41 which areconnected to a refrigerant compressing and condensing arrangement (notshown).

The outlet damper assembly, as shown, includes cooperative upper andlower dampers 41-4111 communicating with separate outlet chambers 42defined between panels 44. The upper and lower dampers 41-41:: areprovided to selectively control flow of tempered air to the downstreamchambers 42 and the air from each chamber 42 is supplied through ductmeans (not shown) to a different space served by the air-conditioningunit. A damper motor 45 is provided for each outlet damper 41-4111 andcan be operated by a remote control thermostat located in a space to beserved by the air conditioner. The thermostats operate damper motors 45to selectively modulate dampers 41-41a to admit proportioned flow ofheated air from chamber 38 and cooled air from chamber 34 to provide aselected blend of tempered air in each chamber 42 to be supplied to theserved space.

In general, motor operator 11 modulates inlet dampers 4 and 6 to providea stream of air to heating element 32 and cooling element 33 at aselected temperature. In situations when the outside temperature is inthe range of the desired temperature in the served space so some spacesrequire cooling and others require heating both heating element 32 andcooling element 33 can be operated and the temperature of the airsupplied to the space served by the unit is controlled by the positionof dampers 41-41a which determine the temperature of the air admitted tochambers 42.

In other cases, depending on the inlet air temperature and thetemperature desired in the served space, only air cooling element 33 orair heating element 32 can be operated so a part of the air streampasses over one of the elements 32 or 33 and the air stream passingthrough the other flow channel is not tempered. The tempered air is thenmixed with untempered air to provide the desired 7 temperature in eachchamber 42. Automatic cut-off switches (not shown) can be provided tocontrol the operation of heating element 32 and cooling element 33 inaccordance with selected changes in outside air temperature and heatingload. Also, in certain operating ranges where the outside airtemperature is only slightly below the desired room temperature both airheating element 32 and air cooling element 33 can be turned off so theentire cooling effect required in the space served by theair-conditioning unit can be supplied by uncooled outside air and anyheating effect can be supplied by mixing the outside air with acontrolled quantity of return air so temperature regulation iscontrolled entirely by the inlet dampers and controller 11.

Also, it will be recognized that if desired the air inlet damperassembly can be controlled by damper motor operator 11 to provide aminimum flow of fresh air at all times, regardless of whether the airflowing through the unit is heated or cooled.

The invention claimed is:

1. An air inlet assembly to supply air to an air conditioning apparatuscomprising: a generally rectangular housing defined by a top wall,bottom wall, spaced first and second side walls and an end wall having areturn air inlet communicating with the space served by the airconditioning apparatus, a fresh air inlet communicating with a source offresh air, and an exhaust air outlet communicating with said return airinlet; means to supply air from said space served by said unit to saidreturn air inlet and to supply fresh air to said fresh air inlet; firstdamper wall means, including first adjustable air damper means, disposedwithin said housing and connected to said first side wall and said endWall to define a return inlet chamber within said housing communicatingwith said return air inlet and said exhaust air outlet; second damperwall means, including second adjustable air damper means, disposedwithin said housing and connected with said second side wall and saidend wall to define a fresh air inlet chamber communicating with saidfresh air inlet, said first and second damper wall means being disposedin spaced converging relation so said second damper means is inpartially facing relation with said first damper means and so airemitted from said second damper means is directed into said stream ofair emitted from said first damper means; damper operator meanscooperating with the said converging first and second wall means toselectively control said first and second adjustable damper means toregulate the quantity of return air and quantity of fresh air flowingthrough said first and second damper means; exhaust fan means disposedto receive air from said return air inlet and exhaust a portion of suchair through said exhaust air outlet; and control means to selectivelyoperate said exhaust air fan means in response to change in temperatureof a selected air stream passing through said housing.

2. The air inlet assembly of claim 1 including: operator means toselectively control said first and second adjustable damper means toregulate the quantity of return air and quantity of fresh air flowingthrough said first and second dampers; exhaust fan means disposed toblow exhaust air through said exhaust air outlet; and, control means toselectively operate said exhaust air fan in respouse to selectedtemperature of air passing through said housing.

3. The apparatus of claim 1 wherein said means to supply said air fromsaid space served by said unit and said means to supply fresh air tosaid fresh air inlet including blower means disposed within said housingin a 5. An air inlet assembly to supply a stream of air to an airconditioning apparatus comprising: side wall means defining an elongaterectangular housing having a return air inlet adjacent a first end ofsaid housing and communicating with the space served by the airconditioning apparatus, a fresh air inlet adjacent said first end ofsaid housing communicating with a source of fresh air, and an exhaustair outlet communicating with said return air inlet; blower meansdisposed within said housing to induce return air flow from said spaceserved by said unit through said return air inlet and to induce freshair flow through said fresh air inlet; first wall means extendingbetween two adjacent Walls of said housing at an oblique angle relativeto the longitudinal axis of said housing and connected with said wallsto form a return air chamber communicating with said return air inletand said exhaust air outlet and including first adjustable air dampermeans to control the flow of return air to said blower means; secondwall means including second adjustable damper means extending betweentwo adjacent walls of said housing at an oblique angle relative to bothsaid Walls to define a fresh air inlet chamber communicating with saidfresh air inlet wherein said first damper means and said second dampermeans are in partially facing relation so air emitted from said seconddamper means and said first damper means is mixed; damper operatordisposed between said converging first and second wall means toselectively control said first and second adjustable damper means toregulate the quantity of return air and the quantity of fresh airflowing through each of the damper means; exhaust fan means disposedwithin said exhaust air chamber to emit exhaust air through said exhaustair outlet; and control means to operate said exhaust air fan means inresponse to selected temperature.

References Cited UNITED STATES PATENTS 6/1967 Norris et al. 16516 2/1968Savage 9838 US. Cl. X.R.

